Blending pump



A ril 20, 1965 O. s. KNEDLIK 3,179,382

BLENDING PUMP Filed March 1, 1963 2 Sheets-Sheet 1 IN VENTOR. 0m?zi'flz'flzm 4 rfaE/VEYS United States Patent This invention relates tofluid metering and mixing pumps and more particularly to an improvedblending pump.

The term blending pump as used herein refers to a variety of pumpespecially used to mix a plurality of fluids together in predeterminedquantities and simultaneously pump the mixture so produced to storagecontainers or mixture processing equipment. As an illustrative example,pumps of this variety are useful in the production of ice cream to blendthe desired quantity of air with a liquid ice cream mix and delivers thefoamed mixture directly into an ice cream freezing machine.

It is an object of the present invention to provide an inexpensive pumpfor accurately blending a plurality of fluids together in predeterminedproportions and delivering the mixture thus formed to a point outsidethe pump.

It is another object of this invention to provide a blending pumpcomposed of a plurality of interchangeable modules which can beassociated in a desired numbet and a desired capacity to effect theblending of predetermined proportions of a desired number of fluids.

It is a further object of the present invention to provide a blendingpump comprising a plurality of modular stages in which a fluid is addedradially of a first stage, metered thereby and pumped axially into anadjacent stage having a larger volumetric capacity and wherein a secondfluid is added radially of the second stage, combined with the firstfluid, and pumped from the second stage axially thereof.

Yet another object of the invention is the provision of a blending pumpcomprising a plurality of individually housed gear pumps axiallydisposed from each other and driven by a common shaft, wherein thediameters of the two gears of each pump set are of diiferent diametersso that the portion of fluid divided from a fluid stream entering theparticular stage and carried around the periphery of one gear iscombined with the fluid carried around the periphery of the other gearat a different point in the fluid stream causing a higher degree ofmixing of the fluids.

A still further object of the invention is the provision of a blendingpump having a plurality of modular stages, each being housed in asubstantially transparent housing as to permit visual observation of theoperation of the pump.

Another object of the present invention is to provide a blending pumpincluding a plurality of dual gear pumps having a common driving means,and wherein adjacent pairs of gears are disposed in substantiallyparallel planes but displaced angularly from coextension with oneanother so that the operation of each stage can be more easily observed.

These and other objects of the invention are more fully set forth in thefollowing detailed explanation having reference to the attached drawingsin which illustrative embodiments of the invention are shown, not tolimit the scope of the invention but in order that the principles of theinvention might be more clearly understood.

It should be recognized that the embodiments shown are merelyillustrative of preferred forms of the blending pump of the inventionandthat many possible modifications thereto can be eliected Withoutdeparting from the principles of the invention.

In the drawings:

"ice

FIGURE 1 is an exploded perspective view of a two stage embodiment ofthe invention;

FIGURE 2 is a perspective View of the assembled blending pump shown inFIGURE 1;

FIGURE 3 is an enlarged sectional View taken along line 53 of FIGURE 2;and

FZGURE 4 is a side elevation View of a multi-staged embodiment of thepresent invention.

Now, with particular reference to the drawings wherein like numeralsdenote like parts among the several figures, a blending pump of theinvention is illustrated generally at id. in the embodiment shown inFIGURES l3 the pump it; comprises a primary stage 12, a secondary stage14 and an exit side cover plate 16. In a preferred form, the housingsif; and 2d of the primary and secondary stages respectively, and thecover plate 16 are all formed from a substantially transparent toughplastic material such as polymethyl methacrylate (Lucite) orpolyoxymethylene (Delrin), although for some applications wherecorrosion and wear may be of particular importance, other materials suchas stainlesssteel can be used. The use of transparent material ispreferred because it allows the operator to observe the operation ofeach stage of the pump and make any process corrections necessary as a Fresult of his observations.

As best shown in FIGURE 1, a substantially figure-S shaped recess isformed in surface of the exit side of each housing, the recess 22 in theprimary stage housing 13 being of'a lesser depth than that of the recess24 in the secondary stage 2% for reasons more. fully set forthhereinafter. The recesses 22 and 24, although lying in substantiallyparallel planes, are angularly displaced from one another so that onlyone lobe of the primary stage recess 22 is coaxial with a lobe of thesecondary stage recess 24-. A pair of intermeshing spur gears 26 iscontained for rotation in the primary stage recess 22 and a second pairof intermcshing spur gears 28 is contained for rotation in the secondarystage recess 24. The larger diameter gear 36? and the smaller diametergear 32 comprising the primary gear pair 26 have the same transversewidth, both being substantially equal in Width to the depth of therecess 22. Likewise, the larger diameter gear 34 and smaller diametergear 36 comprising the secondary ear pair 28 are each equal in width tothe depth of the recess 24. It can thus be seen that because thesecondary stage recess 2 is deeper than the primary stage recess 22 thatthe secondary gear pair 24 is wider than the primary gear pair 22 whenall the gears used have teeth of approximately the same size, it will beseen that there is a greater inter-tooth volume in the gears of thesecondary stage than in those of the primary stage, and that thereforethe total inter-tooth carrying capacity of the gears of the secondarystage is greater than that of the first stage by a fixed amount.

The placement and diameters of the recesses 22; and 24 are such that theouter edges of the teeth of the gears carried therein are so nearlyadjacent the sidewalls 38 of the recesses as to be in sliding contacttherewith.

As best illustrated in FIGURE 1, the smaller gear 32 of the primarystage and the larger gear 34- of the sec ondary stage are removablykeyed to a common drive shaft 40. The shaft 40 is journalled at itsinner end in a shallow recess 4-2 formed in the inner surface or thecover plate 16 and extends through sealingly engaging openings 44 and 46formed through the housings 18 and 29 respectively. The portion of theshaft 49 extending from the housing 18 may have a land 48 machinedthereon as to receive the set screw of a driving pulley (not shown); Thelarger gear 36 of the primary stage is secured to a blind shaft 5i) sojournalled at one end in a shallow recess in the inlet face thesecondary stage housing fitlxand at the other end a shallow'recessformed in the floor of the recess 22.. The smaller gear 3-6 of thesecondary stage is secured to a blind shaft 52 journalled at one end ina shallow recess 54- in the cover plate 16 and at the other by a closelyfitting opening 56 formed in the secondary stage'housing centrally ofthe smallerv In the preferred embodiment of the invention showninFIGURES 13, an inlet conduit 65 is formed in the primary stage housing18 radially thereof as to communicate an opening 62 at the outer edge ofthe'housing 18 with the inlet side 64 of the gear pair 26. The conduit6% may conveniently have interior threads 66 formed in the outer portionthereof as to receive an appropriately sized, threaded conduitrei from afluid supply. The

exit side 7% of the primary stage 12 communicates with an axial conduit77. extendingbetween the exit side ill of the primary gear pair 26 andthe inlet 74 of the secondary gears pair 23.

A fluid inlet conduit '76 is formedin the secondary stage originating athe outer edge of the secondary stage housing 2% and extending radiallyinward thereof to intersect the axial conduit '79. The outlet 78 of -t esecondary gear pair 23 communicates with a mixture outlet conduit 80.formed through the cover plate 16. Similarly to conduit as, theconduits'i and 34 may have interior threads formed, in the outerportions thereof re spectively to;receive a conduit 82 from a secondfluid supply and a conduit 84 to a mixture use or storage container.

The blendingpump It isconveniently assembled as by threading bolts 86through openings formed through the pump axially thereof. A sufficientquantity of suitable noncontaminating sealing compound such as petroleumjelly maybe expressed onto the mating sulffaces ofthe housings l8 and 2tand exit cover plate 16 prior to the assembling of the pump for a moreperfect seal between the stages. 7 J

As willreadily be seen, the blending pump of the in-. vention is quicklyassemblabie and can easily be taken apart for cleaning, sterilizing andreplacement or interchanging of parts.

A second embodiment of the invention is illustrated in FIGURE 4. Thisblending pump tilt? is similar in all respects to the-one shown inFIGURES 1-3 except that v the primary stage Hi2 and secondary stage 164are ,suc-

ceeded by a plurality of additional stages 1696 each hav- I ing aslightly greater volumetric pumping capacity than the stageimmediatelypreceding. As with the firstembodiment the gear pairs (notshown) in successive stages lie insubstantially parallel planes and'areangularly disposed from one another as to permit more easy visualinspection of each stage through the preferably transparent-housings1th; and cover platerlltl. The drive shaft 112 is elongated as tooperatively engage one gear of each intermeshing pair. and has a drivepulley 114 mounted thereon, connected as by an endless belt 116 to theoutput shaft 118 of a suitable motor. Because the pump of the. presentinvention comprises modular stages or units, any; number of stageshaving desired capacities may be as sembled with one another to blenddesired amounts of a selected number of fiuidswith one another toproduce a mixture of definite proportion. V The term fiuicls, as usedherein is. intended to apply to pumpable gases, liquids or solids or anymixtures thereof. 7

OPERATION The operation of the embodiment shown in FIGURES 1-3 will nowbe described as to produce a foamed ice cream freeze mix, being mindfulthat the FIGURE 4 embodiment operates in asimila'r manner, but havingadditional stages.

Primary and secondary stages having the desired difference of volumetriccapacity are selected and assembled as shown.

Theprimarystage inlet conduit fitlis connected I015 supply of liquid icecream -mix, as through threaded conduit 68. This supply may be either agravitationalv or pressurized feed. The secondary stage inlet conduit.76 is connected in like manner to a source of air which may be in thenature of a vcntto the atmosphere or a pressurized air source.Themixture outlet conduit is connected to a receiver of foamed mixreceiver, such;as an icecream freezing machine and the drive shaft 40,is,

engaged by the output shaft of an electric motor and caused to rotate inthe direction of the arrow (FIGURE 3) ata desired speed. T be greaterthe speed, the greater willvbe the. volume of foamed mixture produced,

As best shown in FIGURES 1 and 3, the cream in the 'inlet conduit 66 isdrawn at'the primary stage inlet 64 intothe inter-tooth cavities of thetwo gears Strand 32' of the primary gear pair as to substantially fillthe cavities. The cream stream, thus continuously severedl intotwosubstantially equal, parts, is conveyed aroundthe'nonintermeshingportion of the periphery of the primary gear pair, 26 and recombined. atthe'outlet 70. However, because the gear '30 has a greater diameter thanthe gear 32 and because the rim speed of the two gears is the same, thecream'carried by the larger diameter gear 39 takes a greater amount oftime to reach the. outlet 7t and is thereforerecombined with diiferent,quanta of cream in the cream stream from that=it was divided from at theinleto l. This mechanism serves to. cause a, greater homogenity of themix metered by the first stage.

It can easily be seen that the amount of cream mix metered through thefirststage, because cream mix is a liquid and therefore relativelyincompressible, is substantially wholly dependenton the inter-toothvolume of the gears of the primary stage; The cream mix metered-by theprimary gear pair .26isiforced by the gear pair 26 from the outlet 70,through the axial .conduit72 into the 7 inlet of the secondary stage.-stage gear pair 28 has a larger inter-tooth capacity .as.aforementioned, and because the secondary gear pair 28i is rotated atthe same speed as the primary pair ,26, 21%

Because the secondary suction is created in the axialconduit 72ivwhichis dependent on the magnitude of the capacity diiferencebe The suction,beside drawingthe.

tween the two stages. mix from the primary stage outlet also constantlydraws a fixed volume of air through the secondary stage inlet;

conduit 76. .'This airvis added to the fiuidmix in;the

axial conduit: at such a velocity as to beturbulently, mixed therewithcausing the mixture tofoam. The foamed mix is divided at the secondarystages gear pair inlet and, conveyed around the, nonintermeshingperiphery of the 1 gears 34 and 36 inthe inter-tooth cavities,Againgbew. cause the, inter-tooth cavities associated with each of thegears 34 and 36 is approximately the same size andbecause the gear 34has a greater diameter than the gear 316,.approxl irnately half of theentering foamed mix is metered around each of the gears and the quantaof mix conveyed around the smaller gear 36 reaches the. secondary stageoutlet 73 before that conveyed around the periphery of the larger gear34 causing a greater amount-of mixing than would ibe'thecase ifthe-gears 34'and 36 were ofthe;

same diameter.

Iti can easily'be seen thatgtheamount of air added to: the mix in thesecond stageis dependent on the increase in the capacity of thesecondistage over the first. 'In the preferred embodiment this increaseis derived by increasing the thickness of the gears of the secondarypair and correspondingly increasing the depth of the recess 24 in thesecondary stage housing 20. However, it is contemplated that thisincrease could be provided by other means, as by providing teeth on thesecondary gear pair that would occupy less of the total volume betweenthe root circle and addendum circle of each gear. The amount of airadded by the second stage tothe mix metered by the first stage is alsodependent on the pressure exerted on the air from outside the valve. Airbeing compressible, it can easily be seen that a greater amount of airwill be added through the conduit 76 if it is connected to the pressureside of an air compressor rather than being open to air at oneatmosphere pressure. Therefore, when the blending pump of the inventionis employed to mix a plurality of fluids and at least one of the fluidsis a gas, it is possible to vary the percent composition of the productof the blending pump by varying the inlet pressure of the gaseousconstituent.

The foamed mixture metered by the scondary gear pair 28 is recombined atthe outlet 78 and ejected from the pump through the exit conduit 89. Itshould be understood that in applications where more than two fiuids areblended that additional stages are interposed between the secondarystage and the cover plate and that the outlet 78 of the secondary stagewould lead to the inlet of a tertiary stage having a capacity greaterthan the secondary stage by a proportion equal to the desiredproportional addition of a third fiuid in the tertiary stage; A pump ofthe invention adapted to blend six constituents in fixed proportion isillustrated in FIG- URE 4.

The outlets of the blending pumps and 1% may be connected to foamed mixreceivers such as a storage tank, or they may be connected to mixtureusers such as ice cream or frozen custard freezing machines. Because theblending pump of the invention is a positive displacement pump, it canbe made to eject metered mixture from its outlet into a container havinga considerable internal pressure.

Example I A supply of liquid ice cream mix is connected to the inlet ofthe primary stage of a two stage blending pump of the invention andmetered thereby into the secondary stage which has twice the volume ofthe primary stage. The metered liquid mix traveling through the axialconduit between stages constantly primes the secondary stage, drawingair at 0 pounds gage pressure through the secondary stage inlet to mixwith the liquid ice cream mixture. The two components become one foamyproduct as they turbulently mix in the axial conduit and travel aroundthe peripheries of the secondary stage gears. The foamed product,discharged into a container having an internal pressure of pounds, gage,is consistently composed of /3 part liquid and /3 part air by volume (50percent overrun) due to the compression of the air.

Example 2 A two stage blending pump of the invention is assembled as asecondary stage having three times the capacity of the primary stage.The inlet conduit of the primary stage is connected to a supply ofnoncar-bonated soft drink liquid and supply of carbon dioxide at 0pounds, gage, is connected to the secondary stage inlet conduit. Whenthe pump is operated, two volumes of CO will be metered into everyvolume of soft drink liquid and the frothy product, when ejected fromthe outlet of the second stage into a freezing compartment at 30 pounds,gage, contains /3 soft drink and /3 CO by volume. The product whensemi-frozen is a soft drink product having a percent overrun.

6 Example 3 A three stage blending pump embodying principles of theinvention is assembled from modular units as to have primary, secondaryand tertiary stages of a volumetric capacity ratio of 126118. Thesestages are employed, as above, to accurately blend 1 part soft drinksyrup, 5 parts water and 12 parts carbon dioxide respectively into afrothy mixture, and discharge the mixture into a pressurized freezingchamber to form a semifrozen carbonated soft drink product comprising 1part syrup, 5 parts water and 3 parts CO by volume (i.e. a drink insemi-frozen state that has a 50 percent overrun). The compressibility ofCO accounts for the reduction in its volume-trio proportion in thepressurized freezing chamber.

Although the individual stages have been illustrated as generally round,disk-like members, it should be realized that the shape of the outerperiphery of each stage may be square, rhomboidal or any other shape.

It will now be realized that several preferred forms of the inventionhave been set forth which fully accomplish the objects set forth atthebeginning of this specification and the operation of these preferredforms has been set forth in great detail. However, those skilled in theart will realize that many omissions, additions and substitutions may bemade with regard to the preferred forms shown and explained withoutdeparting from the principles of this invention as set forth herein andtherefore the extent of the invention should be limited only by thespirit and scope of the appended claims.

What is claimed is:

1. Apparatus for effecting the blending of two fluid streams accordingto a predetermined proportion and for pumping the resulting fluidmixture comprising a first disk-like housing having a recess formed inone face thereof as to have two substantially circular interconnectinglobes of equal depth defined by a floor substantially parallel to theassociated housing face, and sidewalls substantially perpendicular tothefloor of the recess, a pair of intermeshing spur gears mounted forrotation in said recess, each gear being of a thickness substantiallyequalling the height of said recess sidewalls and each of a width as toslidably engage the sidewalls; a fluid inlet conduit in the disk-likefirst housing extending radially between the outer edge of the housingand the recess at a point adjacent the intermeshing portion of the gearson that side of the intermeshing portion where the teeth of the twogears move away from one another during the rotating of the gears; asecond disk-like housing having a first face abutting and sealinglyengaging the last named face of the first housing and a second facehaving a recess formed therein as to have two substantially circularinterconnecting lobes of equal depth defined by a floor substantiallyparallel to the second face of said second housing and sidewallssubstantially perpendicular to the fioor of said recess, the recess inthe second housing being deeper than the recess in the first housing bya percentage equalling the desired percentage addition of the secondfluid; a second pair of intermeshing spur gears mounted on the secondhousing recess, each gear being of a thickness substantially equallingthe height of said recess sidewalls and each of a width as to slidinglyengage the sidewalls, a conduit in the second housing, extending axiallythereof between the recess at a point adjacent the intermeshing portionof the second gear pair on that side whence the teeth of the two gearsmove away from one another during the rotating of the gears and thefirst stage recess at a point adjacent the intermeshing portion of thefirst gear on that side whence the teeth of the two gears move towardone another during the rotating of the gears, a second fluid inletconduit in the disk-like second housing extending radially between theouter edge of the second housing and the axial conduit, intersectingsaid axial conduit intermediate the ends thereof; a disk-like coverplate having 37 a first face abutting and sealingly engaging the lastnamed face of the second housing, and an outlet conduit extend ingaxially through said cover plate, said outlet conduit communicatingwith, the recess of the second housing at a point adjacent theintermeshing portion of the second gear pair on that side whence the,teeth of the two gears move toward one another during rotation of thegears a 1 first fiuid directed intothe first "inlet conduit said firstfluid being divided into two portions, conveyed around thenon-,intermeshing portions of the first gear pair in the inter-toothcavities thereof and ejected into the'axial conduit of the secondhousing, a second fluid being directed into the second inlet conduit,turbulently mixed with the first fluid inthe axial conduit, theresulting fluid mixture being divided into two portions, conveyed aroundthe nonintermeshing portions of the first gear pair in the intertoothcavities thereof'and ejected from the second housing through the outletconduit.

2. Apparatus as set forth in claim 1 wherein one spur gear of each spurgear pair has a substantially greater diameter than the other gear ofthe pair, whereby the portions of fluid conveyed around the gears oflarger diameter recombine with different quanta of fluid conveyed aroundthe gears of smaller diameter than the ones from which they were,divided.

3. Apparatus as set forth in claim 1 wherein one'spur' gear of each pairis secured to a single drive shaft for rotation thereon. 5

I 4. Apparatus as set forth in claim 1 wherein the first spur gear pairand the second spur gear pair are mounted for rotation in substantiallyparallel planes, one gear of each pair being secured for rotation onasingle drive shaft extending. axially of said first and second housings,each of saidrhousings and said cover plate being comprised ofsubstantially transparent material, the other gear first spur gearpairbeing angularly disposed from the other gear of the second spur gearas to facilitate complete visual inspection or" the operation of theapparatus. 5. Apparatus for effecting vthe blending of twofiuid streamscomprising a first housing, a pair of intermeshing, counter rotatablespur gears mounted within said housing,

meansdefining-an inlet to and an outlet from said first gear pair insaid housingsaid gear pair comprising a gear of larger diameter and agear, of smallerdiameter,

means defining a fluid inlet insaid housing communicate,

ing with the inlet-of said geaiipair; a second housing, a pair ofintermeshing counter rotatable spur gears mounted within said secondhousing, means defining an inlet to and. an outlet from second gear pairin said housing, said sec..

0nd gear pair being of a greater thickness than said firstge'ar pair andcomprising a gear of largerdiameter and a gear of smaller diameter,:-aconduit extending between the outlet of the first gear pairand the inletof the second gear-pair, means defining a fiuidinlet in thesecond'housr' ing,- said second fluidinlet communicating with the last anamed conduit intermediate the ends thereof and with the exterior ofsaid second housing; and means defining:

an outlet conduit extending from the outlet of the second gear pair. I p

6. Apparatus as set, forth in claim 5 wherein the first and secondhousings are substantially transparent, one 1 gear of each gear pairbeing secured for rotation to a single 7 drive shaft and the other gearof the first gear pair being angularly ,disposedcwith respect to theother; gear of the second gear. pair so as tofacilitate complete visualinspection of the operation of the apparatus.

References Cited by the Examiner UNITED STATES PATENTS CHARLES A.WILLMUTH, Primary Examiner.

GEORGE IMNORTH, Examiner.

5. APPARATUS FOR EFFECTING THE BLENDING OF TWO FLUID STREAMS COMPRISINGA FIRST HOUSING, A PAIR OF INTERMESHING, COUNTER ROTATABLE SPUR GEARSMOUNTED WITHIN SAID HOUSING, MEANS DEFINING AN INLET TO AND AN OUTLETFROM SAID FIRST GEAR PAIR IN SAID HOUSING, SAID GEAR PAIR COMPRISING AGEAR OF LARGER DIAMETER AND A GEAR OF SMALLER DIAMETER, MEANS DEFINING AFLUID INLET IN SAID HOUSING COMMUNICATING WITH THE INLET OF SAID GEARPAIR; A SECOND HOUSING, A PAIR OF INTERMESHING COUNTER ROTATABLE SPURGEARS MOUNTED WITHIN SAID SECOND HOUSING, MEANS DEFINING AN INLET TO ANDAN OUTLET FROM SECOND GEAR PAIR IN SAID HOUSING, SAID SECOND GEAR PAIRBEING OF A GREATER THICKNESS THAN SAID FIRST GEAR PAIR AND COMPRISING AGEAR OF LARGER DIAMETER AND A GEAR OF SMALLER DIAMETER, A CONDUITEXTENDING BETWEEN THE OUTLET OF THE FIRST GEAR PAIR AND THE INLET OF THESECOND GEAR PAIR, MEANS DEFINING A FLUID INLET IN THE SECOND HOUSING,SAID SECOND FLUID INLET COMMUNICATING WITH THE LAST